A requirement for a security barrier was announced by the U.S. Border Patrol. They needed a barrier able to be built from readily available materials. Further, it must be easy to build (not requiring skilled labor) and modular to adapt to varying local conditions and changing scenarios. Embodiments of the present invention are designed for use in various applications. However, initial design criteria were based upon the needs of the U.S. Border Patrol for a barrier to use under a variety of conditions to control border access. Criteria included:                It must be solid to hamper the passing of drugs across it and prevent penetration of bullets to the other side.        It must be robust against degradation of its function while maintaining its structural integrity. Degradation sources include scaling, burrowing under, ramming by vehicles, cutting, and repeated hammering and chipping.        It must inhibit immediate traversal to facilitate apprehension of the transgressor.        It must be maintained at relatively low cost with maintenance easy to perform quickly in order to minimize exposure of maintenance personnel.        It must be usable in all types of geography, including hilly and rough terrain.        It must “work well and last a long time” irrespective of the type and frequency of repairs.        It must minimize the danger to the Border Patrol and other personnel working at the border.        
Because the Border Patrol cannot control what is done on the “foreign side” of the barrier, design criteria must account for this limitation. Of course, such a barrier might be adapted for other uses, especially those for which less stringent requirements may exist.
Previous barrier designs used to aid the Border Patrol have failed to control access across the border. Various designs of wire mesh fences, commonly used in prisons and schools, have been easily destroyed by transgressors. A barrier constructed from surplus temporary airfield landing mat is currently installed between San Diego, Calif. and Tijuana, Mexico. On the border with Mexico, fencing is installed only near population centers. Hence, only as many as 98 Km (60 miles) of the more than 3100 Km (1900 miles) is fenced. The excess steel landing mat will be exhausted long before any significant amount of border is fenced. The steel landing mat barrier is difficult to maintain and is easily circumvented by scaling or digging under the fence, sawing, use of a cutting torch, ramming, etc.
A bollard fence design has been installed as both a primary and secondary barrier (a second barrier located north of the primary barrier) at the same location. This bollard fence is a staggered line of vertically oriented concrete posts spaced at 10–12.7 cm (4–5 inches) and embedded in concrete. The posts are vulnerable to chipping, require concrete forms that must be installed by skilled contractors, and may be vandalized easily while curing. Transgressors can both see through and reach through the bollards, allowing them to pass drugs and even shoot through them. Proposals to enclose the bollards in steel tubes may make them less vulnerable to attack. This still allows transgressors to reach through the fence and still requires skilled contractors to construct and repair them.
In selected areas there are also impediments at low heights for deterring vehicle traffic. A fence has been installed between El Paso, Tex. and Mexico that is aesthetically appealing, but not resistant to vandalism. The fence is constructed of lightweight panels a few inches thick, mounted on support poles a few inches in diameter. Attacks by blunt instruments can easily create gaping holes in the fence. Ramming by a vehicle can severely damage the fence. In addition, resultant openings allow transgressors to transfer illicit items.
Existing designs fail to meet needs of the Border Patrol at a reasonable cost over their life cycle. Embodiments of the present invention provide cost effective solid barriers to human and vehicular intrusion that meet all the requirements of the Border Patrol and similarly situated organizations. Additionally, embodiments may be adapted for commercial or consumer use.